Process and apparatus for producing hollow steel bars



mvq i9 J. P. GORMAN ET AL PROCESS ANDy APPARATUS FOR PRODUCING HOLLOWSTEEL BARS Filed Jan. 9, 1920 2 Sheets-Sheet l Nov. 18, 1924 l,56,53

J. P. GORMAN ET AL PROCESS AND APPARATUS FOR PRODUCING HoLLow STEEL BARSFiled Jan. 9. 1920 I 2 SheeS-Sheet 2 ATTU/M/EY Patented Nov.. I8, 1924.

JAMES rAUL'GomuAN, or WATERVLIET, AND HENRY FRANK wE-GLARZ, or conoEs,

NEW YORK. i

PROCESS AND APPARATUS FOR PRODUCING HOLLOW STEEL BARS.

Application filed January 9, 1920. Seria] No. 350,440.'

To all whom t may cmwem: o Be it known that we, JAMES PAULGOR- MANandlI-IENRY FRANK WEGLARZ, citizens of the United States, and residents,respectively, of VVatervliet and Cohoes, in the the metal to thebreaking down and reduc- .y

ing action of the hammeror rolls.

In ordinary practice, steel is first run into ingots or blooms and isthen subjected to 'a reducing process by annealing and forging orrolling to break up the segregated form of structure produced incastingthe molten metal and reducing the crystalline structure of the metal toa proper form with the carhides in solution.

In forming seamless tubes, the operation is-even more complicated, asthe blooms of metal must first be perforated and drawn down, until theycanbe gripped by dies and worked through drawing dies and over mandrelson the draw-bench. There are, of 3 5 course, the requisite annealingoperations to keep the metal in condition for drawing.

So far as is known to applicants it has not been a practice to producehollow steel bars with walls of any desired thickness, purely 40 by arolling and reduction process,with the usual annealing of the metal, incontradistinction to drawing the metal through a die.

' It is the object of the present invention to produce hollow steel barshavin' the same structural form for any given feormulae'of analysis, asis found in bar steel reduced in the usual manner of annealing forgingand rolling. v

It is a further object of the invention, as

a step in the process of producing hollow steel bars, to cast hollowingots, which may be subsequently subjected to the necessary forging androlling operations, to bring up the yrequisite structural form of thesteel.

Obviously hollow steelbars have almost an indefinite field of usagepermittingithe manufacture of hollow o shafting, hollow bolts and hollowbars for tools and fixtures vof various sorts where lightness` and thestrength of steel is re uired.

The process hereina r defined makes it possible to. produce hollow steelevenv for gun barrels, with the bore approximately to size, or at anrate requiring only the finishing cut an the rifling- This obvia-tes theexpensive and arduous operation of boring through the solid bar. Thestructural form, of the steel, that is, its microstruct-ure will be thesame as though a solid bar had been rolled and bored. The advantages areapparent from the above brief reference.

Referring to the drawings: Fig. 1 is a view of a mould illustrating themanner of casting the hollow ingot. Fi 1a is a plan view.

ig. 2 lillustrates anl ordinary rolling mill and a means of handling theingots and core during the rolling operation, for the difj'ferentpasses.

Figs. 3, 4 and 5 illustratemore in detail the apparatus shown in plan inFigure 2.

In carryin out the process we employ an ingot mould of the usual type orwe may employ a sand mould. In fact, the type of mould for the ingot isnot material. In pouring the molten steel into the mould we provideacore 10, of metal which is sur.

rounded by va. tubular core piece or tube 11, ofba refractory materialsuch as a brick-dust tu e. i

Theuse of the metallic core-bar, with the covering of refractorymaterial prevents the steel from welding to the core-bar and makes itpossible to readily remove the corebar when the ingot has chilled.

It willbe observed that the core is merely a composite structure having.an iron or steel inner core, with the brick tube or similar refractocovering against which the metalmay s rink.

The ingots so cast, if examined microscopically would show the usualcast structure common to molten metals cooled down after being poured.

The ingots thus formed are now annealed to a forging heat and areswedged out under the hammer in the usual manner except that a core ofsteel or iron is inserted in the cored opening of the ingot.

the bars through the rolls.

The" core indicated at 12, is rotated by any suitable means such as thechuck 13, attached to the motor shaft 14, of the motor 15, and isconstantly rotated, throughout the swedging and hammering operations`upon the ingot. A

After being suitably reduced, the bars' are now heated to a. rollingtemperature-"and the hollow bars are given several passes through therolls of the rolling mill R, until the desired size of bar has beenattained.

During each rolling operation a cold mandrel is employed and is rotatedduring the reduction processing of the bar.

'lhe size of the core-bar determines, of course, the size of opening,through the steel bar and it is apparent that the core-bar must .be ofsufiicient length to .permit of the elongation of the bar due to therolling operation.'

As illustrated in the drawing the motor 15, may be under-slung from acarrier 16, runnin upon a track 17, parallel with the axes 'of the rollsof the rolling mill R, so that the bars may be shifted from one roll toanother during the di'erent passes.

'llhe carrier for the motor also has a movement axially in line, withthe movement of |llhis provides for feeding the core with the bar as thelatter passes through the rolls. 'lhe motor or other desired devicesconstantly rotates thecore bar during the rolling of the hollow bar.,

@f course, the bars, during the rolling operation, are from time to;time annealed so that they will take the necessary reduction withoutcracking or scaling.

llt will be 'quite apparent that the crosssectional form of the steelbars will depend upon the form of groove employed in the rolls and theinvention applies as; well to round, square, hexagonal, octagonal or anyother form required.

llf desired a comparatively large core-bar may be employed in theinitial steps of re` duction and core-bars of' lesser diameter may beused after each reduction, j

-lln some instances, this has been found ad'- vantageous particularlywherea'comparatively small tubular opening is required, with unusuallythick surreundingwalls of metal.

'lhe useof mandrels of different sizes will bring the entire body of themetal into an intimate reduction field `so that the' entire lmetalstructure will be homogenous and .quired Working temper and are readyfor machining, or use such as soli-d bar might require. y

'.lhe steel, formed into hollow hars as dea corresponding -mandrels andfeeding them may be mo Lerares `taining a definite interior diameter andwith the rolls working upon the exterior of the bar, there is actually adouble reduction force applied in any given pass of the metal throughthe rolls. rllhe core forms a solid backing against which the steel ofthe ingot or bar 1s swedged by the rolls so that the entire body of themetalcomes within the influence of the swedging or reducing action.Obviously the mechanism for holdin the dified to suit the erigencies ofany particular requirement without departing from the spirit or intentof the invention, which broadlyl stated contemplates produ'cin a hollowingot and maintaining an opening of definite size therethrough, duringthe swedging and rolling operations to Secure the proper character ofreduction of the metal.

l/lhen it is desired -to produce a hollow bar having a non-cylindricalopening therethrough, it is possible to use a core bar of any desiredcross-section.

'.lhis is made possible by using a hollow core bar and injectingacooling medium therethrough.

'lhe cooling medium may, -of course, be either a liquid or Huid, such aschilled air or gas, so long as it will maintain a reduced temperature inthe core bar.

Sil

lll@

Very low temperature air will absorb the Where a core'bar of angularcross-section or non-cylindrical section is employed, the bar is simplyfed in an axial direction as the steel bar is lpassed through the rolls.@bviously it .would be quite'impossible to rotate the core bar withinthe steel underreductidn. A

lFrom the above it is apparent that the invention has an extremely wideapplication either, tothe production, of hollow steel bars, having acylindrical inner and outer surface or to hollow steel bars having acylindrical bore and an Kirregular exterior surface or to bars havingboth the bore and exterior surface of irregular cross-section.

lll/hat we claim as our invention and desire to secure by Letters Patentis 1. 'llhe method ofl producing hollow steel bars which consists incasting a hollow steel ingot, annealing the same and forging over ametallicv core-bar, and. further reducing the structure of the steel byrolling the hollow bars upon metallic core-bars.

lll@

2. An apparatus for producing hollow steel bars which 'consists ofrolling means for reducing the bars b successive passes, means forsupporting anc rotating a core-bar within the steel bar during eachrolling operation, means permitting shifting of the core-bar into axialline corresponding to each pass through the rolls, and means permittingadvancing the core-bar axially during each rolling' operation.

JAMES PAUL GORMAN. HENRY FRANK WEGLARZ.

Witnesses:

ALFRED S. ROWLES, JOHN H` MACKLE.

